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Wang X, Hong Y, Wang Z, Yuan Y, Sun D. High capacities of carbon capture and photosynthesis of a novel organic carbon-fixing microalgae in municipal wastewater: From mutagenesis, screening, ability evaluation to mechanism analysis. WATER RESEARCH 2024; 257:121722. [PMID: 38723359 DOI: 10.1016/j.watres.2024.121722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/29/2024]
Abstract
The development of wastewater treatment processes capable of reducing and fixing carbon is currently a hot topic in the wastewater treatment field. Microalgae possess a natural carbon-fixing advantage, and microalgae that can symbiotically coexist with indigenous bacteria in actual wastewater attract more significant attention. Ultraviolet (UV) mutagenesis and dissolved organic carbon (DOC) acclimation were applied to strengthen the carbon-fixing performance of microalgae in this study. The mechanisms associated with microalgal water purification ability, gene regulation at the molecular level and photosynthetic potential under different trophic modes resulting from carbon fixation and transformation were disclosed. The superior performance of Chlorella sp. MHQ2 was eventually screened out among a large number of mutants generated from 3 wild-type Chlorella strains. Results indicated that the dry cell weight of the optimal species Chlorella sp. HQ mutant MHQ2 was 1.91 times that of the wild strain in the pure algal system, more carbon from municipal wastewater (MW) were transferred to the microalgae and re-entered into the biological cycle through resource utilization. In addition, COD, NH3-N and TP removal efficiencies of MW by Chlorella sp. MHQ2 were found to increase to 95.8% (1.1-times), 96.4% (1.4-times), and 92.9% (1.2-times), respectively, under the extra DOC supply and the assistance of indigenous bacteria in the MW. In the transcriptome analysis of the logarithmic phase, the glycolytic pathway was inhibited, and the pentose phosphate pathway was mainly carried out for microalgal life activities, further promoting efficient energy utilization. Upon analysis of carbon capture capacity and photosynthetic potential in trophic mode, the addition of NaHCO3 increased the photosynthetic rate of Chlorella sp. MHQ2 in mixotrophy whereas it was attenuated in autotrophy. This study could provide a new perspective for the study of resource utilization and microalgae carbon- fixing mechanisms in the actual wastewater treatment process.
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Affiliation(s)
- Xiaoyan Wang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yu Hong
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
| | - Zeyuan Wang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yaqian Yuan
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Dezhi Sun
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-Remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
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Zhang Q, Wu Q, Xie Y, Dzakpasu M, Zhang J, Wang XC. A novel carbon emission evaluation model for anaerobic-anoxic-oxic urban sewage treatment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 350:119640. [PMID: 38029499 DOI: 10.1016/j.jenvman.2023.119640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 10/16/2023] [Accepted: 11/15/2023] [Indexed: 12/01/2023]
Abstract
The proposal of the dual carbon goal and the blue economy in China has sparked a keen interest in carbon emissions reduction from sewage treatment. Carbon accounting in urban sewage plants serves as the foundation for carbon emission reduction in sewage treatment. This paper re-evaluated carbon accounting in the operational processes for urban sewage treatment plants to develop a novel carbon emission evaluation model for anaerobic-anoxic-oxic treatment plants. The results show that the carbon emissions generated by non-carbon dioxide gases far exceed the carbon emissions from carbon dioxide alone. Moreover, the recycling of sewage leads to carbon emissions reduction that offsets the carbon emissions generated during the operation of the sewage plant. Also, the carbon emissions generated by sewage treatment plants are lower than those generated by untreated sewage. The findings and insights provided in this paper provide valuable references for carbon accounting and the implementation of low-carbon practices in urban sewage treatment plants.
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Affiliation(s)
- Qionghua Zhang
- Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Qi Wu
- Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Yadong Xie
- Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Mawuli Dzakpasu
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an, 710055, China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Jiyu Zhang
- Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Xiaochang C Wang
- Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an, 710055, China
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Lin Z, Zhang D, Liu Y, Zhang Z, Zhao Z, Shao B, Wu R, Fang R, Yao J. CO 2/CH 4 separation performance of SiO 2/PES composite membrane prepared by gas phase hydrolysis and grafting coating in gas-liquid membrane contactor: A comparative study. Heliyon 2023; 9:e18760. [PMID: 37560639 PMCID: PMC10407752 DOI: 10.1016/j.heliyon.2023.e18760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023] Open
Abstract
The gas-liquid membrane contactor (GLMC) is a new and promising kind of gas separation technique, but still exhibits limitations, especially in membrane performance. In order to solve the above problems, we fabricated and characterized novel OH/SiO2/PES composite membranes using gas phase hydrolysis and graft coating methods, respectively. In the preparation process, whether to use alkali to pretreat the membrane was used as an evaluation index. The CO2/CH4 separation performance was tested using the modified OH/SiO2/PES hollow fiber membrane as the membrane contactor in GLMC. In the experiment, we conducted a single factor experiment with diethanolamine (DEA) as the adsorbent to analyze the effect of the flow rate and concentration of DEA on the separation of CO2/CH4. The collected gas had a CH4 content of 99.92% and a CO2 flux of 10.1059 × 10-3 mol m-2 s-1 while DEA at a concentration of 1 mol/L was flowing at a rate of 16 L/h. The highest separation factor occurred at this moment, which was 833.67. Overall, the CO2/CH4 separation performance in GLMC was enhanced with the use of the fluorinated OH/SiO2/PES composite membrane.
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Affiliation(s)
- Zhengda Lin
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Dandan Zhang
- Harbin Institute of Technology Hospital, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Yijun Liu
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Zhongming Zhang
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Zhiying Zhao
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Bo Shao
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Rui Wu
- Guangdong Yuehai Water Investment Co., Ltd., Shenzhen, 518021, PR China
| | - Rui Fang
- Harbin Institute of Technology National Engineering Research Center of Urban Water Resources Co.,Ltd., No.73, Huanghe Road, Nangang Dist, Harbin, 150090, PR China
| | - Jie Yao
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
- Harbin Institute of Technology National Engineering Research Center of Urban Water Resources Co.,Ltd., No.73, Huanghe Road, Nangang Dist, Harbin, 150090, PR China
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Chen W, Zhang Q, Hu L, Geng Y, Liu C. Understanding the greenhouse gas emissions from China's wastewater treatment plants: Based on life cycle assessment coupled with statistical data. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 259:115007. [PMID: 37209571 DOI: 10.1016/j.ecoenv.2023.115007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 04/27/2023] [Accepted: 05/10/2023] [Indexed: 05/22/2023]
Abstract
Wastewater treatment plants (WWTPs) are significant contributors to energy consumption and anthropogenic greenhouse gas (GHG) emissions. For achieving carbon reduction in the wastewater treatment industry, the direct and indirect GHG emissions generated by WWTPs need to be understood from a holistic perspective. This study estimated GHG emissions from WWTPs at the country scale by integrating process-based life cycle assessment and statistical data. On-site data were collected from 17 WWTPs of various regions in China. Uncertainty analysis based on Monte Carlo was also performed, so as to provide more reliable results. The results show that life cycle GHG emissions generated from the wastewater treatment process vary from 0.29 kg CO2 eq/m3 to 1.18 kg CO2 eq/m3 based on 17 sample WWTPs. The key factors contributing to overall GHG emissions are also identified as carbon dioxide (fossil) and methane (fossil) to air mainly generated from electricity generation, and methane (biogenic) and nitrous oxide (biogenic) to air mainly generated from wastewater treatment. National average GHG emissions was evaluated with the value of 0.88 kg CO2 eq/m3, with on-site GHG emissions and off-site electricity-based GHG emissions accounting for 32% and 34%, respectively. The total GHG emissions generated from wastewater treatment are 56.46 billion kg CO2 eq in 2020, with Guangdong province having the dominant contribution. Policy suggestions (e.g., further adjusting the electricity grid toward a low carbon structure, improving technology to promote treatment efficiency and energy recovery) were highly recommended so that national GHG emissions of WWTPs can be reduced. In order to achieve the synergy of pollutant removal and GHG emission reduction, policy-making on wastewater treatment should be tailored to specific local conditions.
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Affiliation(s)
- Wei Chen
- School of Geography and Environment, Shandong Normal University, Jinan 250358, PR China; Antai College of Economics & Management, Shanghai Jiao Tong University, Shanghai 200240, PR China.
| | - Qian Zhang
- School of Geography and Environment, Shandong Normal University, Jinan 250358, PR China
| | - Lulu Hu
- School of Geography and Environment, Shandong Normal University, Jinan 250358, PR China
| | - Yong Geng
- School of International and Public Affairs, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Chengqing Liu
- School of Economics, Shandong Normal University, Jinan 250358, PR China; Institute for Carbon Neutrality, Shandong Normal University, Jinan 250014, PR China.
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Pasciucco F, Pecorini I, Iannelli R. A comparative LCA of three WWTPs in a tourist area: Effects of seasonal loading rate variations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 863:160841. [PMID: 36526170 DOI: 10.1016/j.scitotenv.2022.160841] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 11/28/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Although the wastewater treatment is a fundamental utility for the protection of human health and the environment, non-evident drawbacks are associated with it. Wastewater treatment plants (WWTPs) located in tourist areas generally suffer from the seasonal increase in wastewater flow-rate and associated pollution loads. In this study, a Life Cycle Assessment (LCA) of three medium-size urban WWTPs, located in a tourist area in central Italy, was carried out. The study compared the environmental impacts generated by 1 m3 of treated wastewater in low season (LS) and high season (HS). All the material and energy flows involved in the operational phase of wastewater treatment were considered within the system boundaries, including the disposal or recovery treatment of the waste streams generated by the WWTPs, namely screenings, waste from grit removal and wastewater sludge. The analysis was conducted using almost only real data from full-scale plants. In each WWTP, the environmental impacts produced in HS were higher than those generated in LS; therefore, the environmental impacts increased as the loading rate increased. Furthermore, a correlation between WWTP size and environmental performance was observed. Indeed, in 8 out of 11 environmental indicators, the percentage increase in pollutant emissions due to wastewater treatment in HS decreased as the WWTP size increased. Results revealed that larger WWTPs suffered less from seasonal loading rate variations, showing greater flexibility. The existence of a scale factor suggests that the centralization of WWTPs in tourist areas can be an option to enable better treatment performance in terms of environmental impacts. A sensitivity analysis was performed, increasing N2O emission factors from wastewater treatment in LS: considering a 75 % increase, the outcomes found in default LCA were not confirmed. Future research should investigate the operational factors and biological mechanisms that most affect wastewater treatment when significant seasonal variations are present.
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Affiliation(s)
- Francesco Pasciucco
- Department of Energy, Systems, Territory and Construction Engineering (DESTEC), University of Pisa, 56122 Pisa, Italy.
| | - Isabella Pecorini
- Department of Energy, Systems, Territory and Construction Engineering (DESTEC), University of Pisa, 56122 Pisa, Italy.
| | - Renato Iannelli
- Department of Energy, Systems, Territory and Construction Engineering (DESTEC), University of Pisa, 56122 Pisa, Italy.
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Collivignarelli MC, Baldi M, Carnevale Miino M. Thermophilic biological fluidized bed reactor in sludge line reduces greenhouse gas emissions in wastewater treatment system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 848:157794. [PMID: 35932854 DOI: 10.1016/j.scitotenv.2022.157794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/29/2022] [Accepted: 07/30/2022] [Indexed: 06/15/2023]
Abstract
Greenhouse gas (GHG) emissions represent one of the main drawbacks of wastewater (WW) treatment. However, results of a detailed estimation of the emissions can be a valid tool to define optimal solutions for minimizing impact of WW treatment system on the environment. Thermophilic biological fluidized bed reactor (TBFBR) has been recently proposed as an alternative solution for biological sludge minimization in wastewater treatment plant (WWTPs). In this work, 5 diverse scenarios of sludge line composition were studied and combined with 5 diverse sludge disposal options. GHG emissions in 25 combinations were fully investigated to define optimal sludge treatment and disposal option. Results suggested that TBFBR help to reduce net emitted GHGs with respect to scenario with conventional stabilization treatment in sludge line (anaerobic digestion) (-32.3 ± 3.55 %) thanks to (i) the reuse in water line of the aqueous residue of TBFBR as alternative carbon source, (ii) the significant minimization of sludge production, and (iii) the contained impact of gross GHG emissions due to the energy consumption of this process. The strong minimization of sludge also led to a decisive reduction in GHG emissions in the subsequent phases of transport, additional treatments, and final disposal making the choice of the disposal option indifferent on the overall GHG emission estimation. Moreover, the coupling of processes for the simultaneous and preventive maximization of energy recovery (TCH, and AnaD) before sludge minimization in TBFBR determined a limited reduction of GHG emission compared to scenario with TBFBR alone (-3.71 ± 1.47 %).
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Affiliation(s)
- Maria Cristina Collivignarelli
- Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 3, 27100 Pavia, Italy; Interdepartmental Centre for Water Research, University of Pavia, via Ferrata 3, 27100 Pavia, Italy.
| | - Marco Baldi
- Department of Chemistry, University of Pavia, viale Taramelli 12, 27100 Pavia, Italy.
| | - Marco Carnevale Miino
- Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 3, 27100 Pavia, Italy.
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Zhao X, Meng X, Liu Y, Bai S, Li B, Li H, Hou N, Li C. Single-cell sorting of microalgae and identification of optimal conditions by using response surface methodology coupled with life-cycle approaches. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 832:155061. [PMID: 35395299 DOI: 10.1016/j.scitotenv.2022.155061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/01/2022] [Accepted: 04/01/2022] [Indexed: 06/14/2023]
Abstract
Response surface methodology (RSM) has been widely used to identify optimal conditions for environmental microorganisms to maximize degrading pollutants and accumulating biomass. However, to date, environmental impact and economic cost have rarely been considered. In this study, a single cell of microalgae Chlorella sorokiniana ZM-5 was sorted, and its enrichment was carried out for the first time. The optimized conditions by RSM for achieving the highest COD, TN, TP removal and 352.61 mg/g lipid production were 24 h light time, 4.3:1C/N, 7.2 pH, and 30 °C temperature, respectively. Life-cycle approaches were then carried out upon this illustrative case, and the results indicated that the implementation of the above optimal conditions could reduce the total environmental impact by 48.0% and the total economic impact by 10.2%. This study showed the feasibility of applying life-cycle approaches to examine the optimal conditions of a biological process in terms of minimizing environmental impact and economic costs.
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Affiliation(s)
- Xinyue Zhao
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Xiangwei Meng
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Yan Liu
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Shunwen Bai
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Bei Li
- State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Changchun 130033, China; HOOKE Instruments Ltd., Changchun 130033, China
| | - Hang Li
- HOOKE Instruments Ltd., Changchun 130033, China
| | - Ning Hou
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Chunyan Li
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China.
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